Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 97864 — Monument, OR

ZIP code 97864 (Monument, Grant County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 9 and the first fall frost September 27.

Where ZIP 97864 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostMay 9

First frostSep 27

2012 zone6b

Was 6b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Monument, OR…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Monument, OR

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 9median — 50% chance of a later frost

Safe for tender plantsMay 26only 10% chance of frost after

First fall frostSeptember 27median — 10% chance by Sep 9

Growing season139 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 9.

From the NOAA station Monument 2, OR — 2 miles away, elevation 1,995 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 97864

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 28 – Apr 11

SpinachSow outdoors · Mar 28 – Apr 18

Broccoli, cabbageStart indoors · Feb 28 – Mar 14

Broccoli, cabbageTransplant · Apr 18 – May 2

Onion setsPlant outdoors · Apr 11 – Apr 25

PotatoesPlant outdoors · Apr 18 – May 2

LettuceSow outdoors · Apr 11 – Apr 25

Carrots, beetsSow outdoors · Apr 18 – May 2

TomatoesStart indoors · Mar 14 – Mar 28

TomatoesTransplant · May 16 – May 30

Peppers, eggplantStart indoors · Feb 28 – Mar 14

Peppers, eggplantTransplant · May 23 – Jun 6

BeansSow outdoors · May 16 – May 30

Sweet cornSow outdoors · May 16 – May 30

Cucumbers, squashSow outdoors · May 16 – May 30

Fall lettuce, spinachSow outdoors · Aug 2 – Aug 16

GarlicPlant cloves · Sep 13 – Oct 18

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 9) and first fall frost (Sep 27) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 97864 came on Mar 10 — 11 days earlier than the 1991–2020 average (Mar 21).

average
Mar 212026
Mar 10

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 7a in Oregon

624 plants native to the lower 48 states, recorded in Oregon, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Monument, OR.

Soil in Monument, OR

The soil mapped at the center of ZIP 97864 is Drybed — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH7.6slightly alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Drybed silt loam, 1 to 8 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 97864; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Monument, OR

Summer high94 °Faverage high, August

Winter low23 °Faverage low, January

Hot days71days a year at 90 °F or more

Freezing nights158nights a year at 32 °F or less

Growing degree days2,635base 50 °F — the season’s usable heat

Longest day15 h 35 mindaylight on June 21

Shortest day8 h 47 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation15.1 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Monument 2, OR (2 mi away); precipitation: Monument 2, OR (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

978487a

Kimberly, OR · 8 mi

978566b

Long Creek, OR · 17 mi

978747a

Spray, OR · 19 mi

978656b

Mount Vernon, OR · 28 mi

Oregon planting zones →

Questions about 97864

What planting zone is ZIP code 97864?

ZIP code 97864 (Monument, OR) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Monument, OR?

The median last spring frost (32 °F) near 97864 is May 9; after May 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Monument 2 station.

When is the first frost in Monument, OR?

The median first fall frost near 97864 is September 27, giving a median frost-free growing season of 139 days.

When should I plant tomatoes in 97864?

Start tomato seeds indoors around Mar 14 – Mar 28 and set transplants outside around May 16 – May 30, one to three weeks after the median last frost.

How much rain and snow does 97864 get?

About 15.1 inches of precipitation a year (NOAA 1991–2020 normals, Monument 2 station).

How hot do summers get in Monument, OR?

The average high peaks at 94 °F in August, with about 71 days a year at 90 °F or more.

What kind of soil does 97864 have?

The USDA soil survey maps Drybed at the center of ZIP 97864: silt loam, well drained, pH about 7.6 (slightly alkaline).

Did spring come early in Monument, OR in 2026?

Spring leaf-out near 97864 came on Mar 10 in 2026, 11 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Monument, OR?

Long-day onions: the longest day near 97864 is 15 h 35 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 97864 change?

Yes. The 2012 USDA map put 97864 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.